Restore engine compression and performance with this 39mm Piston for QMB139 50cc 4-stroke engines, complete with piston rings pre-installed for quick and easy installation. This piston is a direct replacement for most Chinese GY6 139QMB engines used in 49cc/50cc scooters and mopeds.
Perfect for top-end rebuilds, this OEM-style piston offers a reliable seal, efficient combustion, and smooth operation.
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39mm piston for 50cc 4-stroke QMB139 engines
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Pre-installed piston rings for fast and accurate assembly
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OEM replacement for stock pistons in Chinese GY6 50cc scooters
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Cast aluminum construction for strength and heat resistance
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Ideal for routine maintenance, rebuilds, or top-end repairs
